An accurate count of the number of rounds remaining in a firearm is of great importance to the user. With firearms of any type, particularly handguns, it is frequently difficult, if not impossible, to determine accurately the number of rounds remaining in the firearm. This is particularly true when the firearm is being used in an urgent situation, such as those which occur in law enforcement or combat. Usually in such urgent situations, the user is unable to keep track of the number of rounds discharged, and has no time to manually check the status of the firearm.
This difficulty exists in all types of firearms, including automatic and semi-automatic firearms. The problem is particularly acute with automatic firearms where it can be impossible to count at all the number of rounds due to the discharge rate.
Additionally, the total number of rounds fired through a firearm is also of great importance in order to monitor the service life of the firearm so that proper maintenance can be provided. This is true for not only hand held firearms, but also for large or permanently mounted firearms such as that used by the military. With such information, preventative maintenance can be performed before the firearm fails.
To date there have been various attempts to provide monitoring systems which can provide information regarding the number of rounds remaining. For example, U.S. Pat. No. 5,142,805 to Horne et al discloses a handgun in which a microprocessor counts the number of times the gun's slide mechanically engages a switch. Because this device requires a slide, the gun must be configured to interface mechanically with the monitoring device. This requires retooling of the slide, which, in addition to the expense, limits the ability to use this device as an after market application. For each different type of slide, different interfaces must be provided. Such a device is not readily adaptable for each type of handgun, nor can a single design of such a device possibly fit substantially all types of handguns which are available. For example, such a device cannot be easily adapted to revolvers, which do not have slides. Furthermore, automatic and semi-automatic rifles have internal bolts and carriers, lacking the slide required for this device. There are also substantial durability concerns arising out of the mechanical contact between the slide and the switch.
U.S. Pat. No. 4,146,987 discloses a device for large caliber firearms which includes a weight eccentrically mounted at the end of a long shaft. The weight causes the shaft to rotate in response to the firing of the firearm, actuating a mechanical ratchet. Such a device is not suited for small firearms due to its configuration as well as the extra mass present in the shaft and weight. In addition to the durability problems inherent in such a mechanical counter, this device would probably have difficulty in keeping up with high cycle rates, such as 300 rounds per minute and higher.
There is a need in the art for an accurate monitoring device for counting the number of times a firearm is discharged, particularly which can be easily fitted to all types of firearms, pistols, rifles, shotguns, and which will operate with any type of action, such as single action, double action, semi-automatic and automatic.